And from Nassim Taleb, the key lesson is not black swans but rather two main points. First, we’re better off with no model than with a defective model and incentives matter — especially when they are all upside. Taleb argues the ancients were fully aware of this upside-without-downside asymmetry, and they built simple rules in response. Nearly 4,000 years ago, Hammurabi’s code specified this: “If a builder builds a house for a man and does not make its construction firm, and the house which he has built collapses and causes the death of the owner of the house, that builder shall be put to death.” Simple. Effective.

Richard Thaler argues the toxic ingredients for ruin include risks that are erroneously thought to be vanishingly small, complex technology that isn’t fully grasped by either top management or regulators, and tricky relationships among companies that are not sure how much they can count on their partners.